U.S. patent number 4,953,523 [Application Number 07/421,941] was granted by the patent office on 1990-09-04 for quick release mechanism for the tool of a concrete/asphalt abrader.
This patent grant is currently assigned to Equipment Development Company, Inc.. Invention is credited to Leo Swan.
United States Patent |
4,953,523 |
Swan |
September 4, 1990 |
Quick release mechanism for the tool of a concrete/asphalt
abrader
Abstract
A quick release mechanism for disengaging the cutting blade of a
masonry saw is disclosed. Rotation of a threaded shaft to achieve
axial movement through a closed partially threaded split collar
lowers the cutting tool onto the work surface via a counterpivot
mechanism which simultaneously compresses a gas spring. Only one
half of the collar has threads complementary to those of the
threaded shaft and pivots away from an opposing fixed unthreaded
collar portion. Upon actuation of a release device, the threaded
portion of the split collar pivots to an open position to disengage
the threaded shaft whereby reverse axial movement of the threaded
shaft and resultant upward disengagement of the cutting tool occur
as the gas spring decompresses.
Inventors: |
Swan; Leo (Jefferson, MD) |
Assignee: |
Equipment Development Company,
Inc. (Frederick, MD)
|
Family
ID: |
23672717 |
Appl.
No.: |
07/421,941 |
Filed: |
October 16, 1989 |
Current U.S.
Class: |
125/14; 299/39.3;
451/352 |
Current CPC
Class: |
B24B
7/188 (20130101); B27B 5/30 (20130101); B28D
1/045 (20130101) |
Current International
Class: |
B24B
7/18 (20060101); B24B 7/00 (20060101); B27B
5/30 (20060101); B27B 5/00 (20060101); B28D
1/04 (20060101); B28D 1/02 (20060101); B28D
001/00 (); B24B 023/02 () |
Field of
Search: |
;51/176,177,178,241G
;125/14 ;299/13SS,39 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Rose; Robert A.
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch
Claims
I claim:
1. A quick release mechanism for retracting a cutting or abrading
tool of masonry cutting apparatus from a work surface,
comprising:
tool positioning means, including a cut control linkage and a screw
threaded rod moveable axially to actuate the cut control linkage to
engage the tool upon the work surface;
compression spring means connected to the cut control linkage, said
spring means being compressed when said tool positioning means is
operated to engage a tool upon the work surface;.and
quick release means mounted on said cut control linkage, said quick
release means including a support structure,
a separable split collar housing a first and a second collar
portion, each of said collar portions having an inner surface
engageable with said threaded rod, said first collar portion
further being pivotally affixed to said support structure and
moveable between a closed position and an open position, said inner
surface of said first collar portion also being threaded and
engaging threads on said threaded rod when in said closed position,
said second collar portion being rigidly fixed to said support
structure, said inner surface of said second collar portion being
unthreaded and frictionally engaging said threaded rod, and
manually operable release means attached to said first collar
portion and biased to maintain said first collar portion in said
closed position, said release means being operable when actuated to
pivot said first collar portion away from said second collar
portion to said open portion whereby said compressing spring
expands to drive said cut control linkage axially upward and to
disengage the tool from the work surface.
2. A quick release assembly according to claim 1 wherein said
compression spring means comprises a gas spring.
3. A quick release assembly according to claim 1 wherein said tool
comprises a rotary saw blade.
4. A quick release assembly according to claim 3 wherein said
cutting apparatus includes a frame and wherein said cut control
linkage includes an elongated member pivotally attached to said
frame and having one end connected to said threaded rod and the
other end to said compression spring means.
5. A quick release assembly according to claim 4 wherein said frame
includes a front end and a rear end, said saw blade being mounted
on said front end and additionally including a first set of wheels
mounted on said rear end of said frame and a second set of wheels
mounted on said elongated member at said front end of said frame
adjacent said compression spring means.
6. A quick release assembly according to claim 4 wherein said
release means comprises a spring loaded linear actuator assembly
located on said support structure.
7. A quick release assembly according to claim 4 wherein said tool
positioning means includes means for rotating said screw threaded
rod to lower and position said saw blade on the work surface.
8. A quick release assembly according to claim 7 wherein said means
for rotating comprises a crank assembly attached to the upper end
of said threaded rod.
9. A quick release assembly according to claim 8 wherein said crank
assembly includes a manually rotable handwheel.
10. A quick release assembly according to claim 9 wherein said
first and second collar portions comprise elongated generally
semi-cylindrical members having arcuate inner surfaces.
11. A quick release assembly according to claim 5 wherein said
compression spring means comprises a gas spring including a piston
member and a piston rod member and wherein one of said members is
attached to said elongated member and the other of said members is
attached to said frame.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
Generally this invention relates to cutting tools and more
particularly to a quick release mechanism for disengaging the
cutting tool of a concrete/asphalt abrader used in construction and
maintenance of road surfaces, parking lots, industrial plant floors
and like surfaces made from stone aggregate.
2. Description of the Prior Art
The prior art for disengaging a cutting tool of a concrete/asphalt
abrader from the workpiece has consisted simply of reverse
operation of the engagement means. The prior art has not provided a
quick release tool disengagement assembly, which is simple, safe
and easy-to-use.
Furthermore, the prior art for abraders useable for the above
purposes and readily moveable from one location to another has
relied on the mass of the abrader assembly to hold the tool on or
in the workpiece. It has not provided means to otherwise maintain
the tool under tension during operation and prevent workpiece
irregularities from causing the cutting tool to unintentionally
disengage from the workpiece.
SUMMARY OF THE INVENTION
The main object of the present invention is the provision of a
relatively easy to operate release mechanism for quickly
disengaging the cutting tool of a concrete/asphalt abrader, such as
a cutter, grinder or planer.
Another object is to provide a quick release mechanism which
decreases the time and physical effort required for disengaging a
tool from a workpiece such that the abrader operator can more
efficiently accomplish the complete work task to be performed.
Another object is to provide a quick release mechanism for
disengaging the tool from a workpiece when emergency, safety or
quality control circumstances so dictate.
Yet another object is to provide a quick release mechanism for
disengaging and retracting a tool from a workpiece upon operator
actuation but which exerts, during engagement of the tool, a
tension force to retain the tool in engagement upon the
workpiece.
Briefly, the invention is directed to a quick release mechanism for
a cutting tool including gas spring means which is compressed upon
the engagement of the tool by the manual rotation of a threaded
shaft, the resilient means being permitted to decompress and
disengage the cutting tool upon operation of a lever to disengage a
screw threaded holding surface from the threaded shaft.
Other objects and further scope of applicability of the present
invention will become apparent from the detailed description given
hereinafter. It should be understood, however, that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be better understood from the detailed
description given hereinbelow and the accompanying drawings with
which are given by way of illustration only, and thus, are not
limitative of the present invention and wherein:
FIG. 1 illustrates a side elevational view of the quick mechanism
assembly of a tool engagement/disengagement linkage of a masonry
saw in accordance with the subject invention.
FIG. 2 is a partial side elevational view illustrative of the
collar assembly of the quick release assembly shown in FIG. 1.
FIG. 3A illustrates a transverse cross-sectional view of the collar
assembly of FIG. 2 with the multi-jawed collar in the closed
position.
FIG. 3B illustrates a transverse cross-sectional view of the collar
assembly of FIG. 2 with the multi-jawed collar in the open
position.
FIG. 4 is a partial side elevational view of the gas spring shown
in FIG. 1 in a decompressed state with the cutting tool
disengaged.
DETAILED DESCRIPTION OF THE INVENTION
Generally, in a conventional concrete/asphalt abrader, the cutting
tool is supported by wheels affixed to the rearward end of the main
frame and by wheels affixed to the forward end of a fork assembly,
with the main frame and the fork assembly being pivotally connected
at a mid region between the supporting wheels. In the case of a
concrete masonry saw, a circular cutting blade or disk is attached
to the forward end of the main frame. To use the cutting blade, the
main frame and the fork assembly are pivoted relative to each other
until the blade lowers and engages the workpiece such as a road
surface or a floor of a building to the depth of cut desired.
To pivot the main frame and the fork assembly and thereby engage
the cutting blade, the saw operator moves the cut control linkage
downward which in turn relatively pivots the wheeled end of the
fork assembly upward and the cutting blade end of the main frame
downward. The downward movement of the cutting blade can thus be
continued until the desired depth of blade cut is attained
whereupon the downward movement of the cut control linkage is
terminated. Disengagement of the blade occurs by moving the cut
control linkage upward.
FIG. 1 shows a concrete/asphalt abrader, specifically a rotary
circular saw assembly, supported for use by wheels 2 and 4 which
are mounted on the rear portion of a main frame 6 and the front
portion of a fork assembly 8, respectively. The main frame 6 and
fork assembly 8 are pivotally connected at pivot 7 between wheels 2
and 4. Mounted on the control platform 10 affixed to the handle bar
assembly 12 is a bushing 14. A crank assembly 16 is mounted on the
bushing 14. The assembly 16 consists of a manually rotable
handwheel 18 from which a shaft 20 is supported for rotation within
bushing 14, shaft 20 extending through bushing 14 to engage the cut
control linkage 22 at the collar assembly 24. The handwheel 18 is
rotated by lifting ball knob handle 26 to extract it from a safety
hole 28 in platform 10 and rotating it about the longitudinal axis
of shaft 20.
The upper portion of the shaft 20 has a threaded portion 30, the
threads of which engage complementary threads in the collar
assembly 24, which is described in greater detail hereinbelow. The
cut control linkage 22 upon which the collar assembly 24 is
mounted, extends downward to be pivotally attached at its lower end
to the rear portion of the fork assembly 8. At the front end of the
fork assembly 8, a cylindrical gas spring 32 is pivotally attached
via the lower end of the cylinder piston rod 34. The gas spring 32
extends upward from the front end of the fork assembly 8 and is
connected via its outer cylinder wall to a support structure 36
mounted on the front portion of the main frame 6, as shown in
greater detail in FIG. 4. Additionally, mounted on the front
portion of the main frame 6 is a cutting tool comprising a circular
cutting blade 38.
FIG. 2 shows in greater detail the interrelationship of the collar
assembly 24 with the threaded portion 30 of the shaft 20. To
axially move the shaft 20, the ball knob 18 is lifted upward to
remove the ball knob handle 26 from a safety hole 28 in the
platform 10 and the handwheel 18 is then rotated. As the shaft 20
rotates, the threaded portion 30 engages the complementary threads
on one half of the collar assembly 24 to axially move the cut
control linkage 22 as shown in FIGS. 3A and 3B.
Respectively, FIGS. 3A and 3B show the collar assembly 24 in a
closed position wherein the threaded portion 30 of the shaft 20 are
engaged with the complementary threads of the collar assembly24 and
in an open position wherein the threaded portion 30 of the shaft 20
are disengaged from the complementary threads of the collar
assembly 24.
The collar assembly 24 has a perimeter support wall 40. Within the
support wall 40 is a multi-jawed collar 42 consisting of a fixed
jaw 44 and a pivotable jaw 46, the fixed jaw 44 being secured to
the support wall 40 by fixed tab 48 which is rigidly affixed at
opposite ends to the fixed jaw 44 and the support wall 40,
respectively. The pivotable jaw 46 is attached by a pivot pin 50 to
an extension of the support wall 40. Generally, on the opposite
side of the pivotable jaw 46 from the pivot pin 50, a pivot tab 52
is rigidly affixed thereto. The fixed jaw 44 has a smooth inner
arcuate surface 54 which communicates with the threaded portion 30
of the shaft 20, while the pivotable jaw 46 has a threaded inner
arcuate surface 56 which has threads 58 complementary to those of
the threaded portion 30 of the shaft 20. In addition to the
multi-jawed collar 42, the collar assembly 24 has a release plunger
60, consisting of a plunger shaft 62, a knob 64, a spring 66, a
fixed collar bushing 68, a nut bushing 70 rigidly affixed to the
plunger shaft 62, and an end cap 72. The plunger shaft 62 extends
from the knob 64 through the support wall 40 and through the fixed
tab 48 and the pivot tab 52, with the spring 66 being biased in an
uncompressed state between the support wall 40 and the knob 64 to
push the knob 64 away from the support wall 40 thereby maintaining
the multi-jawed collar 42 in a closed position.
To open the jaws of the multi-jawed collar 42, the knob 64 is
depressed as shown in FIG. 3B causing the plunger shaft 62 to move
through the fixed tab 48 until the nut bushing 70 engages and moves
the pivot tab 52 and pivots the pivotable jaw 46 about the pivot
pin 50 to disengage the threads 58 of the threaded inner arcuate
surface 56 from the threaded portion 30 of the shaft 20. When the
complementary threads 58 are disengaged from the threaded portion
30, the cut control linkage 22 is free to move upward and will do
so under influence of the compressed gas spring 32.
In operation, the operator of the saw shown in FIG. 1 rotates the
handwheel 18 which rotates the shaft 20, the threaded portion 30 of
which, in engaging the complementary threads of the pivotable jaw
46 of the multi-jawed collar 42 moves the cut control linkage 22
axially downward. The downward movement moves the rear portion of
the fork assembly 8 downward, such movement being transmitted via
the pivot connection 7 with the main frame 6 to move the front
portion thereof downward. Consonant with this movement the cutting
blade 38 is lowered onto and into the workpiece e.g. the surface of
a concrete slab on roadway and the piston rod 34 moves upward to
compress the gas spring 32, the cutting blade 38 being held in
engagement with the work surface by the tension force arising from
the compression of the gas spring 32. To quickly disengage the
cutting blade 38 from the workpiece, the release plunger 60 is
actuated to pivot the pivotable jaw 46 of the multi-jawed collar 42
until threads 58 and threaded portion 30 are disengaged thereby
permitting the cut control linkage 22 to move upward as the
decompressive force of the gas cylinder spring 32 is transmitted
through the linkage.
The invention being thus described, it will be obvious that the
same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications are intended to be included within the
scope of the following claims. For instance, it is to be
appreciated that the quick release assembly, while illustrated with
respect to a masonry saw, is adaptable to any concrete/asphalt
surfaces, planer, scarifier, or similar apparatus.
* * * * *